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-rw-r--r--src/libsystemd/sd-bus/bus-track.c34
1 files changed, 30 insertions, 4 deletions
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c
index 6ece2244c2..90e0c7ae01 100644
--- a/src/libsystemd/sd-bus/bus-track.c
+++ b/src/libsystemd/sd-bus/bus-track.c
@@ -32,6 +32,7 @@ struct track_item {
struct sd_bus_track {
unsigned n_ref;
+ unsigned n_adding; /* are we in the process of adding a new name? */
sd_bus *bus;
sd_bus_track_handler_t handler;
void *userdata;
@@ -80,9 +81,23 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(struct track_item*, track_item_free);
static void bus_track_add_to_queue(sd_bus_track *track) {
assert(track);
+ /* Adds the bus track object to the queue of objects we should dispatch next, subject to a number of
+ * conditions. */
+
+ /* Already in the queue? */
if (track->in_queue)
return;
+ /* if we are currently in the process of adding a new name, then let's not enqueue this just yet, let's wait
+ * until the addition is complete. */
+ if (track->n_adding > 0)
+ return;
+
+ /* still referenced? */
+ if (hashmap_size(track->names) > 0)
+ return;
+
+ /* Nothing to call? */
if (!track->handler)
return;
@@ -112,8 +127,7 @@ static int bus_track_remove_name_fully(sd_bus_track *track, const char *name) {
track_item_free(i);
- if (hashmap_isempty(track->names))
- bus_track_add_to_queue(track);
+ bus_track_add_to_queue(track);
track->modified = true;
return 1;
@@ -237,18 +251,30 @@ _public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) {
/* First, subscribe to this name */
match = MATCH_FOR_NAME(name);
+
+ bus_track_remove_from_queue(track); /* don't dispatch this while we work in it */
+
+ track->n_adding++; /* make sure we aren't dispatched while we synchronously add this match */
r = sd_bus_add_match(track->bus, &n->slot, match, on_name_owner_changed, track);
- if (r < 0)
+ track->n_adding--;
+ if (r < 0) {
+ bus_track_add_to_queue(track);
return r;
+ }
r = hashmap_put(track->names, n->name, n);
- if (r < 0)
+ if (r < 0) {
+ bus_track_add_to_queue(track);
return r;
+ }
/* Second, check if it is currently existing, or maybe doesn't, or maybe disappeared already. */
+ track->n_adding++; /* again, make sure this isn't dispatch while we are working in it */
r = sd_bus_get_name_creds(track->bus, name, 0, NULL);
+ track->n_adding--;
if (r < 0) {
hashmap_remove(track->names, name);
+ bus_track_add_to_queue(track);
return r;
}